No power, sluggish acceleration - 1.6 BFQ Engine

[kaspa_lee]

Hey guys,
I just got a 2002 Golf MK4 1.6 (Auto), essentially got this super cheap off a friend who could not fix it.

Essentially it's got little to no power. Acceleration is horrible, probably too dangerous to drive (can't navigate roundabouts quickly e.g.)

Here are a few things I've tried:
- Unplugged MAF, no difference. Replaced and cleaned, no difference.
- A few times, when completely cold and not driven for a few days drove perfectly for about 10 minutes
- Gets worse the longer you drive - will take forever to get up to speed and won't change down gear
- When slamming on throttle it continues/revs slowly in the same gear
- Sometimes changes down a gear and revs very high, but little difference in power

Replaced last year: EGR valve, plug leads, pre-cat sensor

Took it to euro mechanic today and there were a few fault codes - they cleared these but it didn't help. I have no idea what's going on and my friend had gone through a similiar process to no avail.

Sort of deciding whether to just get rid of it, so any help would be appreciated!

[h100vw]

Clearing the faults doesn't make them go away mate. What were the codes they saw.

Does it idle ok and rev freely in neutral?

Is there any oil in the gearbox?

Gavin

Hey guys,
I just got a 2002 Golf MK4 1.6 (Auto), essentially got this super cheap off a friend who could not fix it.

Essentially it's got little to no power. Acceleration is horrible, probably too dangerous to drive (can't navigate roundabouts quickly e.g.)

Here are a few things I've tried:
- Unplugged MAF, no difference. Replaced and cleaned, no difference.
- A few times, when completely cold and not driven for a few days drove perfectly for about 10 minutes
- Gets worse the longer you drive - will take forever to get up to speed and won't change down gear
- When slamming on throttle it continues/revs slowly in the same gear
- Sometimes changes down a gear and revs very high, but little difference in power

Replaced last year: EGR valve, plug leads, pre-cat sensor

Took it to euro mechanic today and there were a few fault codes - they cleared these but it didn't help. I have no idea what's going on and my friend had gone through a similiar process to no avail.

Sort of deciding whether to just get rid of it, so any help would be appreciated!

[epitrochoid]

Check the temperature sensor (should be a green 4 pin sensor), crankshaft and camshaft sensor. If it has an electronic throttle (no cable), check the sensors on the accelerator pedal. If these malfunction, the engine usually only idles and has no power.

REgards
Epitrochoid

[Umai Naa!!]

Timing?

[kaspa_lee]

Clearing the faults doesn't make them go away mate. What were the codes they saw.

Does it idle ok and rev freely in neutral?

Is there any oil in the gearbox?

Gavin

It idles fine and revs freely in neutral. I haven't checked the oil in the gearbox (but it has been changed within the last 2 years to my knowledge). It drives great when completely cold or not used for a period of time - this happens especially when the car is up to operating temp/warm.

Wouldn't it drive okay for a bit if the codes are cleared? (esp if it's a sensor issue)

Check the temperature sensor (should be a green 4 pin sensor), crankshaft and camshaft sensor. If it has an electronic throttle (no cable), check the sensors on the accelerator pedal. If these malfunction, the engine usually only idles and has no power.

REgards
Epitrochoid

How do I check the sensors? Not as in how I find them but how do I assess them? Anyhow here are the codes:




And the codes once they were cleared...

[h100vw]

It idles fine and revs freely in neutral. I haven't checked the oil in the gearbox (but it has been changed within the last 2 years to my knowledge). It drives great when completely cold or not used for a period of time - this happens especially when the car is up to operating temp/warm.

Wouldn't it drive okay for a bit if the codes are cleared? (esp if it's a sensor issue)



How do I check the sensors? Not as in how I find them but how do I assess them? Anyhow here are the codes:




And the codes once they were cleared...

No it wouldn't if there's a problem, why would it. The codes are just reporting what is seen by the ECU. If the fault remains, which it is as it doesn't drive well when warm. Then there is a hard fault you need to fix...

There's every chance that most of those faults are related, you would need a wiring diagram to verify.

Gavin

[kaspa_lee]

Thanks for the replies. What would be some recommendations in terms of next steps?

[h100vw]

It needs scanning again to see what codes still remain after the reset was done.

Gavin

[PoloBlack]

If the engine runs fine in neutral, i am thinking its a gearbox problem. Get the auto serviced as a cheapish starting point (assuming the box isn't kaput)


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[kaspa_lee]

It needs scanning again to see what codes still remain after the reset was done.

Gavin

It was scanned immediately after codes were cleared and returned 00545 Enginge-Transmission Electrical Connection fault.

If the engine runs fine in neutral, i am thinking its a gearbox problem. Get the auto serviced as a cheapish starting point (assuming the box isn't kaput)


Sent from my iPhone using Tapatalk

Hmm. How involved would it be to replace it with a manual box? I'm guessing probably not worth it. Why are euro cars so complicated.

[JustCruisn]

It was scanned immediately after codes were cleared and returned 00545 Enginge-Transmission Electrical Connection fault.



Hmm. How involved would it be to replace it with a manual box? I'm guessing probably not worth it. Why are euro cars so complicated.

About $2k more than fixing the bad connection you have.
00545 - Ross-Tech Wiki

Find the transmission fuse and check it for corrosion etc, number 15 and 31
Check the battery terminals and any ground connections are sound.

Check the connection from Engine Control Unit to Transmisison Control Module, buzz those wires, check the pins are clean the wires are not broken, frayed etc.

[JustCruisn]

This may help also

http://www.vwwatercooled.com/forums/f14/mk4-golf-1-6-automatic-4000rpm-@-100km-h-61656.html

[epitrochoid]

The engine and transmission ECU's are under the plastic plenum cover. It is possible that they have been wet at some stage (they shouldn't get wet but you never know where people stick hoses)
Justcruisn is spot on about what to check.
It sounds like an electrical connection that is bad and when a bit of heat gets into the connector, contact is lost and the ECU goes into a limp mode.

[kaspa_lee]

About $2k more than fixing the bad connection you have.
00545 - Ross-Tech Wiki

Find the transmission fuse and check it for corrosion etc, number 15 and 31
Check the battery terminals and any ground connections are sound.

Check the connection from Engine Control Unit to Transmisison Control Module, buzz those wires, check the pins are clean the wires are not broken, frayed etc.

The engine and transmission ECU's are under the plastic plenum cover. It is possible that they have been wet at some stage (they shouldn't get wet but you never know where people stick hoses)
Justcruisn is spot on about what to check.
It sounds like an electrical connection that is bad and when a bit of heat gets into the connector, contact is lost and the ECU goes into a limp mode.

Cheers guys, I'm hoping this is the case. I checked those fuses and one of them was corroded and I replaced it but no dice.

Weather is pretty bad in Perth at the moment so started getting to the ECU but only got as far as 1 windscreen wiper lol. But then I noticed this...possible cause?

[kaspa_lee]

Hey guys, I've checked the fuses and plugs, I really can't do much except for a visual inspection I don't have a multimeter. I unplugged both the TCM and ECU and cleaned them with some MAF cleaner, the only thing I noticed is that the 'pedal' light now works after I replugged them in. But alas, same issue - limp mode after about 10 minutes driving.

I think I'd like to take it to someone to have it sort it out, would it better to take it to an auto eleccy or a euro specialist?